1. Technical Field of the Invention
The present invention relates to a technology for variably controlling sound receiving characteristics such as directionality.
2. Description of the Related Art
For example, an audio zoom technology for changing sound receiving characteristics such as directionality according to a zoom value of a video camera has been suggested previously. Japanese Patent No. 3109938 discloses a configuration in which a coefficient defining directionality is changed stepwise or linearly according to the zoom value such that the directionality of received sound increases (i.e., as a sound-receiving angle decreases) as the zoom value approaches the telephoto side.
However, in the configuration in which the directionality is changed stepwise, the audio sound sounds unnatural since the acoustic characteristics change discontinuously according to the zoom value. If the coefficient defining directionality is changed linearly, discontinuous change in the acoustic characteristics may be suppressed. However, there is problem in that directionality changes unnaturally with respect to the zoom value since the relationship between the directionality and the zoom value is different from the relationship between acoustic characteristics heard in an actual acoustic space and the distance to the sound source.